Mammoth Locomotive Works Involved in the engineering, construction, and manufacture of large and full-scale locomotives, most for amusement park or other commercial operations.

Mardyke Miniature Railways Mardyke Miniature Railways Ltd is a long established English company, producing garden and commercial railway equipment.

Maxitrak Limited United Kingdom based manufacturer of kit build and ready built passenger carrying miniature railway locomotives and rolling stock.

MDM Locomotive Works Supplies 1½ inch scale diesel locomotive models, power trucks, and accessories. Models are built to the scale of 1½ or 1.6 inches to the foot and to a gauge of either 7¼ or 7½ inch.